1. Technical Field
The present invention relates to a pattern formed structure, a method of forming a pattern, a device, an electrooptical device and electronic equipment.
2. Related Art
As a method of forming a pattern such as a wiring used for electronic circuits, integrated circuits and the like, for example, photolithography has been widely used. However, the photolithography requires large-scale equipments including vacuum device and exposure device and complicated processes are performed to form the wiring having a predetermined pattern in the equipments. In addition, efficiency in use of the material is only about several % and most of the material has to be disposed, resulting in a high production cost.
Meanwhile, a droplet discharge method in which a liquid material is discharged in the form of droplets from a liquid discharging head has been proposed to form patterns. Japanese Unexamined Patent Publication No. 11-274671 is a first example of related art and Japanese Unexamined Patent Publication No. 2000-216330 is a second example of related art. So-called ink-jet method has been used to form the wiring having a predetermined pattern on a substrate (for example, see the first and second examples). In the ink-jet method, a liquid material for patterning (a functional liquid) is provided in a pattern directly on a substrate, and then heat treatment or laser irradiation is performed to the substrate so as to transform into the pattern. Thereby, this method does not require the photolithography and the processes can be considerably simplified. In addition, according to this method, the material is directly provided on the position of the pattern. Therefore, there is an advantage that the amount of the material which is to be consumed to form the pattern can be reduced.
In recent years, circuits in devices have been highly densified. Accordingly, there is a demand for an extremely-fine and thin wiring. However, it was difficult to stably form such fine pattern by the above-mentioned liquid discharge method because discharged droplets spread out on a substrate after they landed on the substrate. Especially, when the pattern is a conductive layer, a liquid bulge is generated from the above-mentioned spread of the droplets and it could cause defects such as braking of wire and short circuit.
A technique to overcome this problem in the liquid discharge method has been proposed. In the technique, a lyophobic quality is given to a surface of a bank which lays out a forming region of a wiring, the functional liquid is discharged toward the forming region of the wiring, and then the wiring whose width is narrower than the in-flight diameter of the functional liquid discharged by the droplet discharge method is formed. According to this technique, the bank sectioning the wiring forming region is formed. Therefore, even if a part of the functional liquid is discharged on the surface of the bank, all the functional liquid flows into the wiring forming region.
The above-mentioned fine wiring pattern can be formed by utilizing a capillary phenomenon. However, the fine wiring pattern formed by the capillary phenomenon has a relatively thin film thickness compared to other wiring patterns. Thereby, a step, which is a difference in level, is formed on the top face of the fine wiring pattern and the other wiring patterns because of the difference in the film thickness. This could be a problem when another thin film pattern and the like is further formed on the top surface of the bank including the other wiring pattern such that the step could cause disconnection, short circuit and the like.